Even though the advantages of minimum tillage agricultural practices in arid and semi-arid soils have been known for some time, their adoption has been rather slow.
One of the problems associated with such practices has been the difficulty associated with providing efficient high speed implements that are capable of placing or “shanking” fertilizer and/or seeds into the soil with uniform precision when the soil is overburdened with a substantial mat or layer of agricultural residue. Heretofore, when employing prior art assemblies for this purpose, the agricultural residue will bunch, pile or “hair pin” against the furrow opening shanks requiring the implement to either be slowed down, or stopped, and the built-up residue removed by the operator from in front of the shank. This same problem becomes even more difficult when the residue is either wet or quite dense or thick. Because of these problems the prior art implements previously used require application methods that result in higher soil disturbance not conducive to minimum tillage procedures.
In addition to the shortcomings noted above, to accommodate the agricultural residue overburden, the shanks must be taller and spaced further apart, (both side-to-side on the same toolbar and front-to-back on multiple toolbars). The side-to-side limitation increases the distances between crop rows per toolbar. This, of course, requires more toolbars. The increased number of front-to-back toolbars, of course, increases the problems associated with turning the implement at the end of the crop rows. For example, when the implement is turned on a corner, or on a side hill the shanks on one toolbar will often line up with the shanks on another toolbar resulting in uneven row spacing and inefficient or duplicate application of fertilizer. Additionally, the increased number of toolbars multiplies the implement framework required to support the increased number of toolbars, thereby substantially increasing the manufacturing and maintenance costs of the implement.
Considerable effort has been expended in providing rather expensive devices, called “coulters”, which are positioned forward of the shanks, and which are operable for cutting or slicing through the residue to minimize the bunching or “hair pinning” of the agricultural residue in front of the respective shanks. One such prior art device is illustrated in U.S. Pat. No. 4,762,075 and which issued on Aug. 9, 1988 to James W. Halford, and which is entitled “Seed/Fertilizer Minimum Tillage Planter”. FIGS. 1–4 of the Halford patent show a prior art “coulter” design; and FIGS. 5–9 show a non-coulter design that has deflector plates 141 which are mounted to the shank 15, and which extend rearwardly and outwardly from the front edge of the shank to deflect agricultural residue (trash) laterally and rearward away from the shank 15. Such a design has the disadvantage of also deflecting some of the soil uprooted by the shank away from the shank, thereby effectively widening the furrow, and compromising the minimum tillage procedure. There are many other patents that show various “coulter” and “non-coulter” designs that are classified in Class 111 of the U.S. Patent Classification System.
Therefore, one aspect of the present invention is to provide a substantially improved, relatively high speed minimum tillage agricultural implement having furrow opening shank assemblies that are more efficient in “shanking” fertilizers or seeds into soils having substantial agricultural residue overburdens.
These and other aspects and advantages of several forms of the present invention will become apparent upon reading the following description of preferred embodiments of the invention along with viewing the drawings.